I'm not sure if this is an unpopular opinion or not but I have seen mostly mixed reception to Emerald, the main protagonist of Pokemon Adventures Emerald Arc.
A main character with the condition, dwarfism or something similar.
I personally think Emerald of Pokemon Adventures is actually not only a well-written character but a very rare well-written teenage character exploring a condition, dwarfism, in the fantasy/sci-fi genre. In fact way before characters like Tyrion Lannister of Game of Thrones became popular, this was the first time I saw any form of media explore dwarfism, this is the first time I even realized this condition existed and it was done pretty well and believable. He's a teenager stuck in an adolescent's body and this teenager literally blends in well in an elementary school/orphanage. He is someone who doesn't like Pokemon yet likes competitive battling, I'm talking about VGC competitive, and it's rooted from his condition. It's from this condition, he's often made fun of by not just kids but by his own cousins after his parents died. He's often bullied as being this helpless kid that is too reliant on the Pokemon he's loved to get him to high places. This causes him to resent not only Pokemon but help from nearly everyone. This constant bullying over his condition has forced Emerald to run away until he meets a certain inventor and later he meets Krystal and Prof. Oak which leads up to the events of the Battle Frontier where he rediscovers his love for Pokemon. Honestly I will admit, design-wise, he has certainly the oddest design for a main character out of not only the Pokemon series but out of the shonen manga genre in general that often feature your tall cocky humorous teenage action hero. He does start out a little annoying at the beginning, but the thing is that was the same reaction Adventure fans had to Ruby and Sapphire. People thought Ruby was too feminine and Sapphire was incredibly different from the May of the anime. It was through good story telling and this funny character dynamic full of chemistry that most, if not all, Pokemon Adventure fans embraced this as the best take on Brendan and May from the games. Similar for Emerald, he starts to grow on you over time, especially someone who understand Gen 3 competitive battling. Some people however do like Emerald's character but still hate him in the end because Kusaka's original idea was to have Wally, another well-written character trying to overcome his breathing disorder, represent Pokemon Emerald version but that idea was scrapped. Some fans however did changed their minds over time with the new design for Emerald in the ORAS series, the kid embracing his short stature and long hair. Looking at him now, he actually looks more like a character from the Pokemon game series than his original design featuring lots of gadgetry and a crescent-shaped head.
Whatever your thoughts are on Emerald, I do actually think he's a well-written character exploring a condition, dwarfism or something similar, at a young age that is actually rarely explored and well-crafted for a teenage main character in almost any popular form of media, especially in science fiction or fantasy, which I bet some of you might find it surprising that it's Pokemon of all the forms of media out there.